70/71/72 402

Tooth

Well Known Member
Supporting Member 1
Tim, my 468 that’s in my nova has 7/16 dimple rods with arp bolts (factory hi perf). My pins are pressed and it has 11-1 .250 dome TRW forged pistons that are close chambered but I have open chamber 116 cc aluminum heads on it= 10.25-1You need to be careful when you mill the heads to make compression. Your intake bolts will not lineup very good if you take too much off and you will have to slot the intake bolt holes a little bit. It also messes with your gasket surfaces. And you can also change the geometry by decking the block. The only way to know for sure is to mock up the new pistons in the block and check your deck height in each hole on the corner. Mine ranges from .006 to .012... my block had a lot of nickel in it and is extremely hard. Most big block Chevy’s only have a couple thousands wear And will usually clean up with just a light hone and de glaze. The machine shop should be able to run a deglazing hone in it and then make it and let you know if the cylinder has any taper or wear.
personally I think it would be pretty tough to get close to 600 hp with less than 10 to 1 compression. It could probably be done but you will have to do your homework. If you look at most GM performance crate engines most of them that make 600 hp are at least 10 to 1. Having zero deck height helps. If the Pistons are still in it you can clean the deck surface and you can check all the corners at TDC to figure out what your deck height is for your quench. another nice possibility is head gasket thickness. Standard is .042 and are available in different thicknesses. I run 91/93 octane in mine.
 
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Tim

Well Known Member
Supporting Member 4
Thanks Tooth, when I did the W it was a bit more forgiving and too 30 off the deck to get it square and zero.
I completely stripped the block and took out the frost plugs and everything else. All the places where oil is is really good, the coolant areas not so much. Not sure how usable the block is with all the crap that came out of it. I was told this was a coolant cooled engine but must have been in salt water at some point. Between the cylinder walls I can’t get the junk out. Any ideas or do I quit while I’m ahead.
 

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Tim

Well Known Member
Supporting Member 4
Armstrong’s where I took my W block has the right stuff. They did my W block that way although it wasn’t near as bad as this one.
 

409gang

Well Known Member
Wow that thing is pretty crusty inside, I don't think I have ever seen one that corroded. Im with you it could have been a boat motor used in salt water, or someone ran it with just water and no antifreeze.
 

Tim

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Supporting Member 4
Around here Steve mostly salt water. A lot will use a coolant system to prevent this. There’s a lot that use raw water cooled but if let sit that’s what happens. I’ve seen fresh water raw water cooled and they are usually ok. My concern with this block is the amount of flake and the size of the flakes. Big blocks are thick and might be ok.
 

Tooth

Well Known Member
Supporting Member 1
A good hot tanking and a good flushing with rolling around will clean it out. Sometimes tapping on it while you’re rolling it around and flushing will help too. James is right though if you use caustic it will help eat that out and then a good HOT water rinse with good pressure will clean it out. I wouldn’t be afraid of it, just don’t get in a hurry and clean it out the best you can with the freeze plugs out you might even be able to get a small brush in there and working around a little bit.
 

Tim

Well Known Member
Supporting Member 4
Tooth, I took the hot water pressure washer to it today and a lot came out. The 2 places between the cylinders where there’s no frost plugs I can’t get at. Ill take it to Armstrong’s. I know they have the hot tank and can sonic check it.
I ordered pistons from Skip White. I’ll wait till they get here and do everything at the same time. They can bore and deck it.
 
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Greg Reimer

Well Known Member
Any time you boil off water, either in a steam boiler or a cooling system, there is rust formed, and un dissolvable solids remain, since they are inert components contained with the water that doesn't boil, so they are left behind. When insufficient anti freeze has been used in a cooing system, rust and scale are the by products. That's stuff that's left behind from the cooling processes. Back in the day of steam power, whether it was ships, stationary generating plants, or steam locomotives on the railroads, enough boiler impurities that remained were often a problem, since the presence of such matter hampered the efficiency of the boiler. In the days of steam locomotives, a novel way of ridding the lower reaches of the boiler of rust, scale, and other bad stuff was to find the lowest point of the boiler and put a remote controlled blow off valve of some sort at that location pointing down and out away from the rest of the train, usually under the cab pointing out the side. Periodically, the engineer would throttle up his engine, then open the valve and allow the boiler to blow all that rusty muck and debris out of the boiler under pressure to clear it out. A couple minutes per side was usually sufficient. There's a tale of an old woman who lived in a white painted two story wood farmhouse about 40 feet from the tracks. She was a constant complainer, always calling to report stuff, either real or imagined, and she was quite the pest. One fine day, a veteran engineer had his boiler pressure at or near the maximum, and he did a long blow down at about 60 miles per hour going past her house. Seemed nobody had cleared that boiler of sediments and rust for several trips, so it was quite loaded up. The result was that the once white painted farmhouse looked like it was made of red adobe like they have in New Mexico or Arizona. Doesn't pay to aggravate the wrong people!
 
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Barry Taylor

Well Known Member
Supporting Member 2
Finding someone that still uses caustic soda is impossible here in the Dallas area. The parts washers that most shops use are about as good as my dish washer. They are good for what there called but not removing scale rust and paint. The machine shop that i use now takes the blocks to aplace that bakes em in an oven and they come out clean inside and out. Then the machine work starts. JMO
 

Tooth

Well Known Member
Supporting Member 1
Tooth, I took the hot water pressure washer to it today and a lot came out. The 2 places between the cylinders where there’s no frost plugs I can’t get at. Ill take it to Armstrong’s. I know they have the hot tank and can sonic check it.
I ordered pistons from Skip White. I’ll wait till they get here and do everything at the same time. They can bore and deck it.
Nice pistons, they are pretty fast. Have an excellent tech support too....:good
 
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